Lifting dolly

ABSTRACT

A lifting dolly for manual operation, particularly by a single operator, comprises a base member provided with caster wheels and with an upwardly extending post on which a first operating lever is rotatably mounted and slidably and rotatably connected with a second lever which is slidably and rotatably mounted on the post and provided with a lift fork at its front end for insertion beneath a load object to be raised and transported. The first lever has a dead center position, at both sides of which the weight of the levers, with or without the weight of the load, tends to counteract operation of the levers.

United States Patent [191 [in 3,876,096

a e l. L t k l Ap 8 1975 i 1 LIFTING DOLLY Primary E.\aminer-Albert J. Makay [76] Inventor, Chester G Latek 7317 Attorney, Agent. or Firm-Hill Gross, Simpson, Van

Pottawatomi Dr Palos Heights. ill. Samen Steadman Chiara & Simpson 60463 221 Filed: Mar. 20, 1974 ABSTRACT [21] Appl. No.: 452,943 A lifting dolly for manual operation. particularly by a single operator, comprises a base member provided [52] U S Cl ZMISOP 714/77 R H4606 with caster wheels and with an upwardly extending 254/8 254/114 post on which a first operating lever is rotatably [5 1] Int Cl 04 mounted and slidably and rotatably connected with a Fie'ld 378484 second lever which is slidably and rotatably mounted 252N114 8 on the post and provided with a lift fork at its front end for insertion beneath a load object to be raised and transported. The first lever has a dead center posi- [56] References cued tion, at both sides of which the weight of the levers.

UNITED STATES PATENTS with or without the weight of the load, tends to coun- 2 36(l 799 10/1944 Slingsby s. 214/506 teract operation of the levers. 3.5121163 5/1970 Guerrico 214/38 R 7 Claims, 4 Drawing Figures LIFTING DOLLY This invention relates to a novel and improved lifting dolly for manual operation. which is particularly suitable for easy operation by a single person in raising, transporting and lowering an object, such as a piece of furniture and the like.

An object of the invention is to provide a lifting dolly of the type indicated above which is simple and inex pensive to manufacture and to operate. in addition to being highly efficient and dependable Another object of the invention is to provide a lifting dolly of the kind indicated which includes a substan tially flat, horizontal base member having a supporting post extending upwardly therefrom with which two manually manipulatable operating levers are connected, one for rotary motion on a transverse horizontal axis and the other for rotary and slidable motion on a supporting pin which is secured to said post and parallel with said axis, said levers being rotatably and slidably interconnected, and said other lever being provided with a lifting fork at one end thereof which by manual operation of said levers is movable between a lower position beyond one end of said base member and a raised position in which it rests on said base member.

Other objects and advantages of the invention will become evident from the following description of a preferred embodiment of the invention with reference to the accompanying drawing, in which FIG. 1 is an elevational side view of the dolly showing in full lines the lifting fork and lever in position with the lifting fork inserted beneath a tilted object and in dotted lines the lifting fork and lever with the lifting fork in raised position.

FIG. 2 is a rear end view of the dolly seen in the direction of the arrows ll-Il in FIG. 1,

FIG. 3 is a vertical section of the lifting dolly along line llllIl in FIG. 4. with the lifting fork raised and re tracted to rest on the dolly base. and

FIG. 4 is a top view of the lifting dolly seen in the direction of the arrows lVlV in FIG. 3.

In the embodiment shown, a dolly base member, or platform. 2 of rectangular configuration is provided with two supporting caster wheels 4 adjacent the front end of said base member 2 and with two similar caster wheels 6 at the rear end thereof In the rear region of the base member 2 a support member 8 is firmly secured to the top of said base member 2. Said support member 8 comprises two upright parallel side plates, or posts, 10 extending longitudinally of the base member 2 and joined together along their bottom edges by an integral cross member 12 which is secured to the top of the base member 2 by welding or by any other suitable means.

At the rear end of said support member 8 each of the side plates 10 is provided with an extension 14 which projects downwardly into a recess 16 at the rear end of the base member 2. Said extensions 14 are provided with a pair of aligned holes for receipt of a first pin 18 which extends horizontally and transversely of the base member 2 and rotatably supports a first lever 20 centrally between said extensions 14.

A second pin 22, parallel with said first pin 18, extends through aligned holes in the side plates 10 adjacent the upper and front edges of said side plates. A second lever 24 is generally U-shaped in configuration with the two legs 26 of the U interconnected at one end by a transverse handle bar 28 and provided with a pair of depending parallel ears 30 which extend longitudinally of the legs 26 and have aligned elongate slots 32 therethrough in which the end portions of said second pin 22 are slidably received. To the other end of said legs 26 a lifting fork 34 in the form of an angle plate is firmly secured, with one flange 34' thereof being substantially horizontal and extending forwardly at the front end ofthe dolly. The top surface of said flange 34' is preferably covered with a piece of felt 35, and the front surface of the upright flange 34" may be provided with one or more pieces 37 of rubber, felt or other soft material, as indicated. Two transverse, parallel rods 36 are secured to the legs 26 at a location between the rear end of the ears 30 and the handle bar 28 where the legs 26 are offset in the direction toward each other. so that between said rods 36 and said offset portions of the legs 26 a substantially rectangular open space is formed through which said first lever 20 passes with a degree of play, particularly in relation to said rods 36.

In operation, when an object 40, such as a piece of furniture, is to be lifted and/or moved. the operator grasps the handle bar 28 with one hand and the free end portion of said first lever 20 with the other hand, The first lever 20 is rotated on the pin 18 until it occupies the position shown in full lines in FIG 1 and in dotted lines in FIG. 3, whereby the second lever 24 through the action on the same by the rear rod 36 is moved forwardly until the pin 22 engages the rear end of the slot 32 as shown in full lines in FIG. 1. ln this position of the first lever 20, the second lever 24 is rotated on the pin 22 to lower the lifting fork 34 to or into close proximity of the floor, as required, and the entire dolly is moved forwardly by pushing action on either one or both of the first lever 20 and the second lever 24 for insertion of the flange 34' beneath the object 40. If necessary, said insertion may be facilitated by slightly tilting said object, and the flange 34 may for the same purpose be provided with a more or less sharp front edge, as indicated at 42.

With the flange 34' thus inserted beneath the object 40 downwardly pressure is exerted on the handle bar 28 for raising the lifting fork 34 to the position shown in dotted lines in FIG. 1, whereupon the first lever 20 is pulled rearwardly at the same time as forwardly pressure is exerted on the handle bar 28, if necessary, in order to maintain the flange 34' in position beneath the object 40. Said rearwardly pull on the first lever 20 causes the same to turn on the rear rod 36, thereby moving the dolly on its caster wheels 4, 6 in a forwardly direction, as indicated by the arrow 50, until the lifting fork 34 is above the front end portion of the base member 2 and the pin 22 is in engagement with the front end of the slot 32, as shown in FIG. 3. The manual pressure on both levers 20 and 24 may then be released so that the lifting fork 34 comes to rest on the platform 2.

If the object 40 is ofa dimension longitudinally of the dolly which significantly exceeds the corresponding dimension of the flange 34', or if the weight of the portion of the object 40 projecting forwardly beyond said flange is greater than the weight of the portion resting directly on the flange 34', it may be necessary to manually tilt the object 40 back to upright position on said flange 34' before the dolly is moved on its caster wheels from one location to another.

Although the dimensions of the lifting dolly according to the invention may vary within rather wide limits,

it has been found that a dolly of this kind for use in an average home may advantageously have a base member 2 which is about 8 to l() inches long and about 8 inches wide, levers 20 and 24 which are about 27 inches long, side plates of about 7 inches height, and a lifting fork 34 of about 8 inches length transversely of the dolly with flanges 34' and 34" of about 4 inches size. These are, of course, merely exemplary dimensions.

An important consideration is that relative dimensions and arrangement of the various components be such as to render the first lever rotatable to both sides of a vertical center line through the pin 18, whereby the weight of the movable parts both with and without a load object on the lifting fork 34 tends to prevent movement of the first lever 20 across said vertical center line through the pin 18. it may also be pointed out that with a lifting dolly of the approximate size indicated by the above exemplary dimensions, it

will in most cases be possible for an operator with average arm length, when standing at the rear end of the dolly. to reach across the same and use one hand for tilting the object 40 to facilitate the insertion of the flange 34' beneath the same and also for tilting said object in the opposite direction to straighten it up after said insertion of the flange.

It is obvious that the invention provides a very simple. reliable and versatile lifting dolly for the purposes indicated. Many modifications of the nature and com bination of the components of the dolly are feasible and intended to be included within the scope of the appended claims.

I claim as my invention:

1. A lifting dolly for manual operation, comprising a. a substantially flat, horizontal base member supported on front and rear caster wheels attached thereto.

b. a supporting post secured to said base member and extending upwardly therefrom at a location sub stantially between said front and rear caster wheels.

c. a first lever for manual operation.

d. means connecting one end of said first lever to said base member in the rear region thereof for rotation in relation thereto on a horizontal axis extending transversely of said base member,

e, a second lever for manual operation.

f. means connecting a longitudinally intermediate portion of said second lever to the top portion of said supporting post for rotation of said second lever on a horizontal axis and for longitudinal slidable motion of said second lever on said intermediate connecting means through a predetermined limited distance.

g. a lifting fork secured to the front end of said second lever and having a forwardly extending load supporting flange for insertion beneath said load, and

h. means interconnecting said first and second levers in a region between the ends of said first lever and between said intermediate connecting means and rear end of said second lever for limited combined rotational and sliding motion of said first and second levers in relation to each other,

LII

whereby said first and second levers may be manually manipulated by an operator grasping the rear end portions of said levers for lowering said lifting fork forwardly of said base member, insertion of said lifting fork beneath a load object, raising and lifting fork to a level above said base member, retracting said lifting fork rearwardly to a position above the front region of said base member and substantially rearwardly of said front caster wheels, releasing said lifting fork to permit it to rest upon said base member, and moving said lifting dolly on said caster wheels from one location to another.

2. A lifting dolly according to claim 1, in which one of said levers extends slidably through an aperture in the other lever which is of such dimension longitudinally of said other lever as to permit said rotational motion between the levers.

3. A lifting dolly according to claim 2, in which one of said levers is substantially U-shaped and said aperture is formed by adjacent portions of the legs of said U-shaped lever and two spaced members extending transversely between said leg portions.

4. A lifting dolly according to claim 1, in which said means connecting a longitudinally intermediate portion of said second lever to the supporting post comprises a downwardly projecting ear on said intermediate portion of the second lever, said ear having a longitudinally extending slot therein in which a horizontal transverse pin secured to said post is slidably received.

5. A lifting dolly according to claim 4, in which said second lever is substantially U-shaped and adjacent substantially parallel portions of the legs of said U- shaped lever are each provided with one of said depending ears, said transverse pin extending through the slots in both of said ears.

6. A manually operable lifting dolly, comprising a caster wheel mounted substantially flat horizontal base member having a front end and a rear end and being provided adjacent said rear end with a supporting post which includes a pair of transversely spaced, longitudinal side plates through which two transverse, horizontal supporting pins extend in parallel relation to each other, one adjacent said base member at the rear end of said supporting post and the other at a higher level adjacent the front end of said supporting post, a first manually operable lever having one end rotatably mounted on said one supporting pin, and a second manually operable lever having a section intermediate the ends thereof rotatably and longitudinally slidably mounted on said other supporting pin, said first lever being rotatably and longitudinally slidably connected with said second lever at a location between the rear end of said second lever and said intermediate section thereof, and a lifting fork being secured to the front end of said second lever, whereby said lifting fork by operation of said levers is movable from a low position in front of said base member and a raised, retracted position in which it rests on top of said base member.

7. A manually operable lifting dolly according to claim 6, in which said first lever has a vertical dead center position, at both sides of which the weight of said interconnected levers tends to counteract movement of said first lever to and past said dead center position. 

1. A lifting dolly for manual operation, comprising a. a substantially flat, horizontal base member supported on front and rear caster wheels attached thereto, b. a supporting post secured to said base member and extending upwardly therefrom at a location substantially between said front and rear caster wheels, c. a first lever for manual operation, d. means connecting one end of said first lever to said base member in the rear region thereof for rotation in relation thereto on a horizontal axis extending transversely of said base member, e. a second lever for manual operation, f. means connecting a longitudinally intermediate portion of said second lever to the top portion of said supporting post for rotation of said second lever on a horizontal axis and for longitudinal slidable motion of said second lever on said intermediate connecting means through a predetermined limited distance, g. a lifting fork secured to the front end of said second lever and having a forwardly extending load supporting flange for insertion beneath said load, and h. means interconnecting said first and second levers in a region between the ends of said first lever and between said intermediate connecting means and rear end of said second lever for limited combined rotational and sliding motion of said first and second levers in relation to each other,
 2. A lifting dolly according to claim 1, in which one of said levers extends slidably through an aperture in the other lever which is of such dimension longitudinally of said other lever as to permit said rotational motion between the levers.
 3. A lifting dolly according to claim 2, in which one of said levers is substantially U-shaped and said aperture is formed by adjacent portions of the legs of said U-shaped lever and two spaced members extending transversely between said leg portions.
 4. A lifting dolly according to claim 1, in which said means connecting a longitudinally intermediate portion of said second lever to the supporting post comprises a downwardly projecting ear on said intermediate portion of the second lever, said ear having a longitudinally extending slot therein in which a horizontal transverse pin secured to said post is slidably received.
 5. A lifting dolly according to claim 4, in which said second lever is substantially U-shaped and adjacent substantially parallel portions of the legs of said U-shaped lever are each provided with one of said depending ears, said transverse pin extending through the slots in both of said ears.
 6. A manually operable lifting dolly, comprising a caster wheel mounted substantially flat horizontal base member having a front end and a rear end and being provided adjacent said rear end with a supporting post which includes a pair of transversely spaced, longitudinal side plates through which two transverse, horizontal supporting pins extend in parallel relation to each other, one adjacent said base member at the rear end of said supporting post and the other at a higher level adjacent the front end of said supporting post, a first manually operable lever having one end rotatably mounted on said one supporting pin, and a second manually operable lever having a section intermediate the ends thereof rotatably and longitudinally slidably mounted on said other supporting pin, said first lever being rotatably and longitudinally slidably connected with said second lever at a location between the rear end of said second lever and said intermediate section thereof, and a lifting fork being secured to the front end of said second lever, whereby said lifting fork by operation of said levers is movable from a low position in front of said base member and a raised, retracted position in which it rests on top of said base member.
 7. A manually operable lifting dolly according to claim 6, in which said first lever has a vertical dead center position, at both sides of which the weight of said interconnected levers tends to counteract movement of said first lever to and past said dead center position. 